1. Field of the Invention
The invention relates to the use of a powderous coating material composition for coating ink-jet recording materials.
2. Description of the Related Art
Polyvinyl alcohols are used in papercoating slips as cobinders in order to enhance the gloss and whiteness of the papercoating. Coats on paper, especially for ink-jet papers, are exposed to a high mechanical load. The coatings are therefore required to have high abrasion resistance. Moreover, the formulation must ensure effective ink absorption, without the ink drop running.
From DE-A 10232666 it is known that silane-containing polyvinyl alcohols are high-grade binders for coating slips. In DE-A 3519575 a combination of silane-modified polyvinyl alcohol and colloidal silica is recommended as coating material for producing a covering coat for heat-sensitive recording paper. EP-A 1080940 describes a water-resistant coating material composition comprising silane-functional polyvinyl alcohol and titanium chelate complex.
JP-A 10-119430 coats heat-sensitive recording materials using an aqueous solution comprising silane-modified polyvinyl alcohol, an isobutylene-maleic anhydride-maleimide terpolymer, metal salt, and crosslinker. The use of silane-modified polyvinyl alcohol as a papercoating agent is also recommended in U.S. Pat. No. 4,617,239, the silanized polyvinyl alcohol being used in an alkaline aqueous solution in combination if appropriate with an aqueous polymer latex. From EP-A 1127706 an ink-jet recording material is known which is coated with a mixture of an aqueous solution of a silanized polyvinyl alcohol, an aqueous polymer latex, and a pigment dispersion.
A disadvantage of the prior art mixtures is the often inadequate storage stability of the polyvinyl alcohol solutions. When mixtures of polyvinyl alcohol solutions and polymer dispersions are employed it is often not possible to achieve the desired end concentration, owing to the sharp viscosity rise when relatively highly concentrated solutions or dispersions are employed.
An object which existed, therefore, was that of providing a coating material composition for producing coatings on ink-jet recording materials, with which, on both paper-based and polymeric substrate materials, abrasion-resistant coatings are obtained; with which an unwanted rise in viscosity during preparation can be avoided; and with which a greater flexibility is achieved in terms of the solids content of the coating slip.